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Hello FreeSurfer Developers,

I'm extracting beta values ​​from some analyzes and I would like to know if I'm extracting and interpreting these values ​​correctly.

To extract the beta values ​​I used this command: 
mri_segstats --seg lh.cortisol_CSF.glmdir/cortisol_CSF_slope/perm.th20.neg.sig.ocn.mgh --i lh.cortisol_CSF.glmdir/beta.mgh --excludeid 0 --avgwf lh.cortisol_CSF.beta.clusters.dat

The model consists of 1 group and 1 covariate.
I used the contrasts for intercept and slope.
The beta values ​​extraction file contains 2 lines (image below).

  • Would the first line be the beta value for the intercept and the second line for the slope?
  • Thus the glm equation for the 1st cluster would be:   cortical thickness = 2.57 - 0.12X + n

Is this correct?

Thanks in advance!

Laura Willers de Souza 

Master Student in Biochemistry

Zimmer Lab - Federal University of Rio Grande do Sul 

- Porto Alegre/RS - Brazil